<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
    <meta name="description" content="Configure viewer to add a button enabling look at a mobile device with cardboard.">
    <meta name="cesium-sandcastle-labels" content="Beginner, Showcases">
    <title>Cesium Demo</title>
    <script type="text/javascript" src="../Sandcastle-header.js"></script>
    <script type="text/javascript" src="../../../ThirdParty/requirejs-2.1.20/require.js"></script>
    <script type="text/javascript">
    require.config({
        baseUrl : '../../../Source',
        waitSeconds : 60
    });
    </script>
</head>
<body class="sandcastle-loading" data-sandcastle-bucket="bucket-requirejs.html">
<style>
    @import url(../templates/bucket.css);
</style>
<div id="cesiumContainer" class="fullSize"></div>
<div id="loadingOverlay"><h1>Loading...</h1></div>
<div id="toolbar"></div>
<script id="cesium_sandcastle_script">
function startup(Cesium) {
    'use strict';
//Sandcastle_Begin
var viewer = new Cesium.Viewer('cesiumContainer', {
    vrButton: true,
    terrainProvider: Cesium.createWorldTerrain()
});
// Click the VR button in the bottom right of the screen to switch to VR mode.

viewer.scene.globe.enableLighting = true;
viewer.scene.globe.depthTestAgainstTerrain = true;

// Follow the path of a plane. See the interpolation Sandcastle example.
Cesium.Math.setRandomNumberSeed(3);

var start = Cesium.JulianDate.fromDate(new Date(2015, 2, 25, 16));
var stop = Cesium.JulianDate.addSeconds(start, 360, new Cesium.JulianDate());

viewer.clock.startTime = start.clone();
viewer.clock.stopTime = stop.clone();
viewer.clock.currentTime = start.clone();
viewer.clock.clockRange = Cesium.ClockRange.LOOP_STOP;
viewer.clock.multiplier = 1.0;
viewer.clock.shouldAnimate = true;

function computeCirclularFlight(lon, lat, radius) {
    var property = new Cesium.SampledPositionProperty();
    var startAngle = Cesium.Math.nextRandomNumber() * 360.0;
    var endAngle = startAngle + 360.0;

    var increment = (Cesium.Math.nextRandomNumber() * 2.0 - 1.0) * 10.0 + 45.0;
    for (var i = startAngle; i < endAngle; i += increment) {
        var radians = Cesium.Math.toRadians(i);
        var timeIncrement = i - startAngle;
        var time = Cesium.JulianDate.addSeconds(start, timeIncrement, new Cesium.JulianDate());
        var position = Cesium.Cartesian3.fromDegrees(lon + (radius * 1.5 * Math.cos(radians)), lat + (radius * Math.sin(radians)), Cesium.Math.nextRandomNumber() * 500 + 1750);
        property.addSample(time, position);
    }
    return property;
}

var longitude = -112.110693;
var latitude = 36.0994841;
var radius = 0.03;

var modelURI = '../../SampleData/models/CesiumBalloon/CesiumBalloon.glb';
var entity = viewer.entities.add({
    availability : new Cesium.TimeIntervalCollection([new Cesium.TimeInterval({
        start : start,
        stop : stop
    })]),
    position : computeCirclularFlight(longitude, latitude, radius),
    model : {
        uri : modelURI,
        minimumPixelSize : 64
    }
});

entity.position.setInterpolationOptions({
    interpolationDegree : 2,
    interpolationAlgorithm : Cesium.HermitePolynomialApproximation
});

// Set initial camera position and orientation to be when in the model's reference frame.
var camera = viewer.camera;
camera.position = new Cesium.Cartesian3(0.25, 0.0, 0.0);
camera.direction = new Cesium.Cartesian3(1.0, 0.0, 0.0);
camera.up = new Cesium.Cartesian3(0.0, 0.0, 1.0);
camera.right = new Cesium.Cartesian3(0.0, -1.0, 0.0);

viewer.scene.postUpdate.addEventListener(function(scene, time) {
    var position = entity.position.getValue(time);
    if (!Cesium.defined(position)) {
        return;
    }

    var transform;
    if (!Cesium.defined(entity.orientation)) {
        transform = Cesium.Transforms.eastNorthUpToFixedFrame(position);
    } else {
        var orientation = entity.orientation.getValue(time);
        if (!Cesium.defined(orientation)) {
            return;
        }

        transform = Cesium.Matrix4.fromRotationTranslation(Cesium.Matrix3.fromQuaternion(orientation), position);
    }

    // Save camera state
    var offset = Cesium.Cartesian3.clone(camera.position);
    var direction = Cesium.Cartesian3.clone(camera.direction);
    var up = Cesium.Cartesian3.clone(camera.up);

    // Set camera to be in model's reference frame.
    camera.lookAtTransform(transform);

    // Reset the camera state to the saved state so it appears fixed in the model's frame.
    Cesium.Cartesian3.clone(offset, camera.position);
    Cesium.Cartesian3.clone(direction, camera.direction);
    Cesium.Cartesian3.clone(up, camera.up);
    Cesium.Cartesian3.cross(direction, up, camera.right);
});

// Add a few more balloons flying with the one the viewer is in.
var numBalloons = 12;
for (var i = 0; i < numBalloons; ++i) {
    var balloonRadius = (Cesium.Math.nextRandomNumber() * 2.0 - 1.0) * 0.01 + radius;
    var balloon = viewer.entities.add({
        availability : new Cesium.TimeIntervalCollection([new Cesium.TimeInterval({
            start : start,
            stop : stop
        })]),
        position : computeCirclularFlight(longitude, latitude, balloonRadius),
        model : {
            uri : modelURI,
            minimumPixelSize : 64
        }
    });

    balloon.position.setInterpolationOptions({
        interpolationDegree : 2,
        interpolationAlgorithm : Cesium.HermitePolynomialApproximation
    });
}

//Sandcastle_End
    Sandcastle.finishedLoading();
}
if (typeof Cesium !== "undefined") {
    startup(Cesium);
} else if (typeof require === "function") {
    require(["Cesium"], startup);
}
</script>
</body>
</html>
